Power supply/demand control system

ABSTRACT

In order to effectively supply and demand electric power between an electric power supplier and a node or a group of nodes individually having an electric power generator, the present invention provides an electric power supply and demand management system capable of obtaining the difference between the total of electric power supplied from the electric power supplier to the node or group and the total of electric power consumed by the electric power loads of the node or group and capable of transmitting information for increasing/decreasing the amount of electric power supply so that the difference becomes smaller to the electric power supplier.

TECHNICAL FIELD

The present invention relates to a distributed electric power generationsystem comprising an electric supplier and consumers for efficientlycontrolling and managing the supply and demand of electric power.

BACKGROUND ART

In recent years, energy-saving measures have been taken significantly inview of environmental protection including the prevention of thegreenhouse effect owing to carbon dioxide, although not so significantlyas those during the oil crisis owing to oil shortage. Consumers ofelectric power are classified into industrial consumers and householdconsumers; the electric power consumption by the industrial consumersstays almost constant after 1970s, but the electric power consumption bythe household consumers has increased twice or more after 1970s. Hence,additional energy-saving measures are required to be taken for householdconsumers.

At present, the great majority of electric power generated by electricpower supplier sides, such as hydraulic, thermal and atomic electricpower generation, is transmitted by a system comprising electric powertransmission lines, substations, etc. and supplied to consumer sides,such as households and factories. In this kind of large electric powergeneration system, heat generating simultaneously with electric powergeneration cannot be used, and the loss of electric power transmissionfrom electric power stations to consumers is large, whereby the finalenergy efficiency is low. Particularly in household consumers havingmany distributed loads with low amount of electric power consumption,energy efficiency becomes low.

For this reason, attention is paid recently to the so-called distributedelectric power generation, that is, electric power generation bysmall-scale electric power generators near electric power consumptionregions, and in particular, attention is paid to cogeneration-typeelectric power generation wherein electric power is generated by a gasturbine or a fuel cell and waste heat generated during electric powergeneration can also be used.

In this kind of distributed electric power generation, each of nodes,such as a household, a factory, a company, a building and a school,itself has an electric power generator, and the node purchases lackingelectric power from an outside commercial electric power system (anelectric power company, an electric power supplier or the like) andsells extran electric power to an electric power supplier, therebyperforming the so-called “trading of electric power.”

Even in this kind of distributed electric power generation, if the saleof electric power to a commercial electric power system is carried outregardless of the present electric power demand, a transmission lossoccurs in the case when a node that sells electric power is distant froman electric power supplier who purchases the electric power; however,conventionally, electric power should only be generated at one locationand transmitted efficiently to locations near consumers; hence, ifcontractors who sell electric power are few, the transmission system isnot affected greatly.

However, if each node sells extran electric power, transmission costchanges greatly depending on the distributions of electric power sellinglocations and electric power consuming locations. Accordingly, thepresent invention is intended to provide an electric power supply anddemand management system capable of reducing the transmission loss andcontrolling and managing the supply and demand of electric powerefficiently by selecting a node that can sell electric power from theelectric power generator thereof the anode to an electric power supplierdepending on the demand at the other nodes.

Furthermore, when a fuel cell is used as an electric power generator atthe node, a time lag of at least one to two hours occurs until a fuelgas, such as hydrogen or propane gas, and oxygen are supplied to thefuel cell and then electric power generation starts. For this reason,when electric power is generated at a node, such as a dwelling house,wherein electric power demand greatly changes depending on time, season,or the like, the amount of electric power generated by the fuel cellcannot be controlled promptly depending on the change in the electricpower demand at the node, whereby generated electric power becomesexcessive or lacking. This causes a problem, that is, theabove-mentioned node must purchase lacking electric power from theoutside in spite of having an electric power generator or sell excessiveelectric power to the outside.

Accordingly, the present invention is intended to provide an electricpower supply and demand management system capable of allowing a fuelcell used as an electric power generator to generate an appropriateamount of electric power, not excessive nor lacking, depending on thesupply and demand at each node.

DISCLOSURE OF INVENTION

The present invention relates to an electric power supply and demandmanagement system including an electric power supplier, an electricpower transmission system, and electric power consuming nodes, each ofwhich having an electric power generator, connected to the electricpower transmission system and classified into a plurality of groups,characterized by comprising, a first calculation unit for obtaining adifference between a total of electric power supplied from the electricpower supplier to the node or group and a total of electric powerconsumed by an electric power load of the node or group, and a firsttransmission unit for transmitting information for increasing/decreasingan amount of electric power supply to the electric power supplier sothat the difference becomes smaller.

It is effective that the first calculation unit determines at least oneof a selling price of electric power from the electric power supplier tothe node or group and a purchase price of electric power from the nodeor the group to the electric power supplier, by using the differencebetween a total of electric power supply from the electric powersupplier to the node or group and a total of electric power consumed byan electric power load at the node or group as a parameter, and thefirst transmission unit transmits at least one of the selling price andthe purchase price to the node or group.

It is effective that the electric power supplier has a reception unitfor receiving information selected from the group consisting of anelectric power charge, an amount of electric power consumption and anelectric power supply capacity of the node or the group, the firstcalculation unit determines an amount of electric power and a purchaseprice of electric power demanded by the electric power supplier for eachnode, which can sell electric power among the nodes, on the basis of theinformation, and the first transmission unit transmits at least one ofthe amount of electric power and the purchase price demanded by theelectric power supplier to the node.

It is effective that the node or the group is provided with; a secondtransmission unit for transmitting information selected from the groupconsisting of an electric power charge, an amount of electric powerconsumption and an electric power supply capacity to other nodes, groupsor the electric power supplier; a second reception unit for receivinginformation selected from the group consisting of an amount of electricpower, a purchase price of electric power and a selling price ofelectric power demanded by the other nodes, groups or the electric powersupplier; and a control unit for controlling an output of the electricpower generator of the node on the basis of the information.

It is effective that the electric power supply and demand managementsystem comprises a node information storage unit for storing nodeinformation including a node identifier for identifying the node and anamount of electric power consumption and an amount of electric powersupply of the node identified by the identifier, and that the firstcalculation unit calculates an amount of transmittable electric powerfrom one node to other nodes and/or the electric power supplier by usingthe amount of electric power consumption and the amount of electricpower supply included in the node information as parameters, the firsttransmission unit transmits a signal indicating the amount oftransmittable electric power to each node, and the node transmits thetransmittable electric power to the other nodes and/or the electricpower supplier.

It is effective that the electric power supplier has a substation, thefirst calculation unit calculates a purchase amount of electric powerand a purchase price of electric power, which are demanded by theelectric power supplier, by using electric power supply and demandinformation regarding a flowing direction and an amount of energybetween a high-voltage side to a low-voltage side of the substation, andthe first transmission unit transmits the amount of electric power to bepurchased and the purchase price to the node or the group.

It is effective that the node is provided with a storage battery, and asecond calculation unit for determining at least one selected from thegroup consisting of a purchase amount of electric power, a purchaseprice of electric power, a selling amount of electric power and aselling price of electric power, which are demanded for the other nodes,by using information regarding electric power demand and storage amountsof storage batteries connected to other nodes, and the secondtransmission unit transmits at least one selected from the groupconsisting of a purchase amount of electric power, a purchase price ofelectric power, a selling amount of electric power and a selling priceof electric power to at least one of the electric power supplier and theother nodes.

It is effective that the first calculation unit or the secondcalculation unit predicts an amount of electric power consumption at thenode or the group and determines an amount of electric power supply,which is demanded by the node or the group, by using the predicted theamount of electric power consumption as a parameter, and the firsttransmission unit or the second transmission unit transmits a signal inorder for an electric power generator of a node or a group other thanthe node or the group, or for the electric power supplier to supply theamount of electric power.

It is effective that the electric power supply and demand managementsystem comprises further electric power consumption amount storage meansfor storing information regarding an amount of electric powerconsumption at each node, and that the first calculation unit or thesecond calculation unit predicts an amount of electric power consumptionat each node or each group by using the stored amount of electric powerconsumption as a parameter.

It is effective that the first calculation unit or the secondcalculation unit determines an amount of electric power supply from thenode by using data including a relation between an output of theelectric power generator and an amount of fuel consumption asparameters.

It is effective that the first calculation unit or the secondcalculation unit determines an amount of electric power supply from theelectric power generator by using at least the amount of electric powerconsumption at the node as a parameter.

It is effective that the first calculation unit or the secondcalculation unit determines an amount of electric power supply of eachelectric power generator so that the number of electric power generatorsin operation of the nodes becomes minimum or maximum.

It is effective that the first calculation unit or the secondcalculation unit predicts an amount of electric power consumption ateach node by using schedule information.

It is effective that the first transmission unit or the secondtransmission unit transmits information for increasing/decreasing anamount of electric power supply from the storage battery of the eachnode or the electric power generator connected to the storage battery toa node, which requires electric power, by using information regarding astorage amount of the storage battery or information regarding atransfer amount of energy of each node.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view showing the configuration of an electric power supplyand demand management system in accordance with Embodiment 1 of thepresent invention.

FIG. 2 is a view showing the configuration of an electric power supplyand demand management system in accordance with Embodiment 2 of thepresent invention.

FIG. 3 is a view showing the configuration of an electric power supplyand demand management system in accordance with Embodiment 3 of thepresent invention.

FIG. 4 is an example of a table of bid information including theidentification numbers of nodes, selling price of electric power andselling amount of electric power.

FIG. 5 is a view showing the configuration of an electric power supplyand demand management system in accordance with Embodiment 4 of thepresent invention.

FIG. 6 is a view showing the configuration of an example of a circuitfor accurately measuring voltage.

FIG. 7 is a view showing the configuration of an electric power supplyand demand management system in accordance with Embodiment 5 of thepresent invention.

FIG. 8 is a view showing an example of a table of the amount of electricpower consumption memorized in storage means in every time zone.

FIG. 9 is the flowchart of a program for determining the operation of aCPU.

FIG. 10 is an example of data representing the relation between theoutput of an electric power generator and the usage amount of fuel.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention relates to an electric power supply and demandmanagement system provided with an electric power supplier as typifiedby an electric power company, an electric power transmission system,electric power generators and electric power consuming nodes connectedto the above-mentioned electric power transmission system and classifiedinto a plurality of groups, and further provided with a firstcalculation unit for obtaining the difference between the total ofelectric power supplied from the electric power supplier to the node orthe group and the total of electric power consumed by the electric powerload of the node or the group and a first transmission unit fortransmitting information for increasing/decreasing the amount ofelectric power supply so that the difference becomes smaller to theelectric power supplier. Namely, the present invention relates to asystem for managing the supply and demand of electric power between anelectric power company and consumers having their own electric powergenerators.

The first calculation unit is mainly used to function for the electricpower supplier and may be provided for any one of the electric powersupplier, the electric power transmission system and the electric powerconsuming node. Furthermore, the first calculation unit may be providedfor each group including a plurality of nodes.

When the information for increasing/decreasing the amount of electricpower supplied so that the difference between the total of electricpower supplied from the electric power supplier to the node or group andthe total of electric power consumed by the electric power load of thenode or group becomes smaller can be sent from the first transmissionunit to the electric power supplier as described above, electric powergeneration at the electric power supplier can be carried outefficiently, thereby it is so effective. The electric power load meansone or more electric power consuming apparatuses including electricappliances, such as a refrigerator, a washing machine, an airconditioner and a television set.

Next, it is effective that the first calculation unit determines atleast one of a selling price of electric power from the electric powersupplier to the node or the group and a purchase price of electric powerfrom the node of the group to the electric power supplier, by using thedifference between a total of electric power supply from the electricpower supplier to the node or the group and a total of electric powerconsumed-by an electric power load at the node or the group as aparameter, and the first transmission unit transmits at least one of theselling price and the purchase price to the node or the group.

With this, each node or group, that is a consumer side, can purchaselacking electric power promptly and securely, and electric poweradditionally stocked in its electric power generator can be purchased byother nodes or the electric power supplier without wasting such anelectric power, whereby the electric power supplier can manage thesupply and demand of electric power efficiently.

Furthermore, it is effective that the electric power supplier has areception unit for receiving information selected from the groupconsisting of an electric power charge, an amount of electric powerconsumption and an electric power supply capacity of the node or thegroup, the first calculation unit determines an amount of electric powerand a purchase price of electric power demanded by the electric powersupplier for each node, which can sell electric power among the nodes,on the basis of the information, and the first transmission unittransmits at least one of the amount of electric power and the purchaseprice demanded by the electric power supplier to the node.

With this configuration, depending on the actual condition of each nodeor group, electric power excessively generated by its electric powergenerator or stocked therein can be purchased by the electric powersupplier without wasting the electric power, whereby the electric powersupplier can manage the supply and demand of electric power moreefficiently.

Hence, it is effective that the node or the group is provided with; asecond transmission unit for transmitting information selected from thegroup consisting of an electric power charge, an amount of electricpower consumption and an electric power supply capacity to the outside(other nodes, groups or said electric power supplier); a secondreception unit for receiving information selected from the groupconsisting of an amount of electric power, a purchase price of electricpower and a selling price of electric power demanded by the outside; anda control unit for controlling an output of the electric power generatorof the node on the basis of the information.

In this way, if each node or group transmits the information selectedfrom the group consisting of the electric power charge, the amount ofelectric power consumption and the electric power supply capacity to theoutside by using the second transmission unit, the node or group canreceive the information selected from the group consisting of thepurchase price of electric power and the selling price of electric powerfrom the outside by using the second reception unit, thereby theelectric power generator thereof can be controlled securely withoutcausing waste.

It is effective that the electric power supply and demand managementsystem is provided with a node information storage unit for storing nodeinformation including a node identifier for identifying the node and anamount of electric power consumption and an amount of electric powersupply of the node identified by the identifier, and that the firstcalculation unit calculates an amount of transmittable electric powerfrom one node to other nodes and/or the electric power supplier by usingthe amount of electric power consumption and the amount of electricpower supply included in the node information as parameters, the firsttransmission unit transmits a signal indicating the amount oftransmittable electric power to each node, and the node transmits thetransmittable electric power to the other nodes and/or the electricpower supplier.

The above-mentioned node information storage unit may only be theso-called storage unit and may be provided for any one or more of thenode, the group and the electric power supplier, and is mainlycontrolled by the above-mentioned electric power supplier. Furthermore,this node information storage unit is connected to the first calculationunit of the electric power supplier, and the first calculation unitcalculates the amount of transmittable electric power from one node toother nodes by using the amount of electric power consumption and theamount of electric power supply included in the node information asparameters, whereby the amount of transmittable electric power can betransmitted from the one node to the other nodes. In other words,electric power generated or stocked excessively at each node can be usedeffectively at other nodes.

The electric power supplier may have a substation. In this case, it iseffective that the first calculation unit calculates a purchase amountof electric power and a purchase price of electric power, which aredemanded by the electric power supplier, by using electric power supplyand demand information regarding a flowing direction and an amount ofpower (energy) between a high-voltage side to a low-voltage side of thesubstation, which may be measured by a magnetic field for example, andthat the first transmission unit transmits the amount of electric powerto be purchased and the purchase price to the node.

Hence, the electric power supplier can effectively use electric powerdepending on the condition of the substation thereof and the like andcan effectively control the substation.

In addition, the node should preferably have a storage battery. In thiscase, each node can stock electric power by itself and can examine theselling time of the stocked electric power depending on the change inthe price of electric power in the market including the other nodesand/or the electric power supplier.

In this case, it is effective that each node is provided with a secondcalculation unit for determining at least one selected from the groupconsisting of a purchase amount of electric power, a purchase price ofelectric power, a selling amount of electric power and a selling priceof electric power, which are demanded for the other nodes, by usinginformation regarding electric power demand and storage amounts ofstorage batteries connected to other nodes, because the secondtransmission unit can transmit the demanded amount of electric power andthe purchase price of electric power to at least one of the electricpower supplier and the other nodes.

Furthermore, it is effective that the first calculation unit or thesecond calculation unit predicts the amount of electric powerconsumption at a predetermined node or group and determines the amountof electric power supply to the predetermined node or group by using thepredicted amount of electric power consumption as a parameter, and thatthe transmission unit or second transmission unit transmits a signal inorder for to the electric power generator of a node or group other thanthe predetermined node or group to supply the amount of electric power.

In this case, it is effective that the electric power supply and demandmanagement system is provided with electric power consumption amountstorage means for storing information regarding an amount of electricpower consumption of each node, and that the first calculation unit orthe second calculation unit predicts an amount of electric powerconsumption of each node or each group by using the stored amount ofelectric power consumption as a parameter. The electric powerconsumption amount storage means may be provided at each node or theelectric power supplier, or the node information storage unit mayfunction as the electric power consumption amount storage means.

Moreover, it is effective that the first calculation unit or the secondcalculation unit determines the amount of electric power supply from thenode by using data including the output of the electric power generatorand the amount of fuel consumption required for the output asparameters.

Still further, it is effective that the first calculation unit or thesecond calculation unit determines the amount of electric power supplyfrom the electric power generator by using at least the amount ofelectric power consumption at the node as a parameter.

It is effective that the first calculation unit or the secondcalculation unit determines the amount of electric power supply of eachelectric power generator so that the number of electric power generatorsin operation at the node becomes minimum or maximum.

It is effective that the first calculation unit or the secondcalculation unit predicts the amount of electric power consumption ateach node by using information regarding the schedule of the componentsor the electric power consuming apparatuses at each node.

It is effective that, by using the storage amount of the storage batteryor the transfer amount of electric power at each node, the firsttransmission unit or the second transmission unit transmits informationfor increasing/decreasing the amount of electric power supplied from thestorage battery at the each node or the electric power generatorconnected to the storage battery to a node requiring the electric power.One calculation unit may function as the first calculation unit and thesecond calculation unit.

Hence, in the electric power supply and demand management system inaccordance with the present invention, the electric power supplier mayhave the substation and the control unit in addition to the firstcalculation unit and the first transmission unit, and each node may havethe second calculation unit, the second transmission unit, the storagebattery and the control unit in addition to the electric powergenerator. The node information storage unit and the electric powerconsumption amount storage means may be provided anywhere if they arecommunicated electrically with each other.

All of these components are at least electrically connected andconstitute the electric power supply and demand management system inaccordance with the present invention. Furthermore, the electric powersupply and demand management system in accordance with the presentinvention should only be provided with the minimum componentscorresponding to at least the functions and effects. Hence, componentscapable of attaining predetermined functions and effects can be combinedappropriately, and the system may preferably have all the components.

Although typical examples of the electric power supply and demandmanagement system in accordance with the present invention will bedescribed below more specifically referring to the accompanyingdrawings, the present invention is not limited only thereto.

EMBODIMENT 1

Next, preferable embodiment in accordance with the present inventionwill be described referring to the drawings.

FIG. 1 is a view showing the configuration of an electric power supplyand demand management system in accordance with Embodiment 1 of thepresent invention. The electric power supply and demand managementsystem shown in FIG. 1 comprises an electric power supplier 1, n (n≧2)nodes 2 and an electric power transmission system 3, and the node 2 hasan electric power generator 4, such as a fuel cell, a storage battery 5,and electric power consuming apparatuses 6, such as a refrigerator, awashing machine, an air conditioner and a television set, wherebytemporary excessive or lacking electric power can be adjusted by thestorage battery 5.

The electric power supplier 1 has a first calculation unit 1 a forobtaining the difference between the total of electric power suppliedfrom the electric power supplier 1 to the node 2 (or a group of aplurality of nodes 2) and the total of electric power consumed byelectric power load at the node 2 (or a group of a plurality of nodes 2)and a first transmission unit for transmitting information forincreasing/decreasing the amount of electric power supply so that thedifference becomes smaller to the electric power supplier. Hence, theelectric power supplier can efficiently control its own electric powergeneration.

In addition, by using the difference between the total of electric powersupplied from the electric power supplier to the node or group and thetotal of electric power consumed by electric power load at the node orgroup as a parameter, the first calculation unit determines at least oneof the selling price of electric power from the electric power supplierto the node or group and the purchase price of electric power from thenode or group to the electric power supplier, and the first transmissionunit transmits at least one of the selling price and purchase price tothe node or group.

The storage battery 5 has an electric power storage unit for storingelectric power and an electric power management unit (not shown) formanaging the amount of the electric power stored in the electric powerstorage unit; the electric power management unit monitors the currentflowing through the electric power storage unit, grasps electric poweramount information, that is, information regarding the amount ofelectric power storage, and transmits the electric power amountinformation to an electric power selling/purchasing system 7. Hence, theelectric power selling/purchasing system 7 may include a control unit, asecond calculation unit, a second transmission unit and a secondreception unit.

Furthermore, the electric power selling/purchasing system 7 receives theelectric power storage amount of the storage battery and transmits theidentification number of the node to which the system it self belongs, asalable amount of electric power, etc. to the electric powertransmission system 3 by using small pulses. Moreover, a meter 8provided for electric power lines led from electric power transmissionlines constituting the electric power transmission system 3 into thenode 2 transmits information regarding the identification number of thenode 2, the salable amount of electric power and the purchasable amountof electric power (in other words, transfer amount information regardingthe transfer amount of energy) to the electric power transmission system3 by using small pulses. This meter 8 may be included in the electricpower selling/purchasing system 7 as a matter of course.

The information transmitted by the electric power selling/purchasingsystem 7 used as the second transmission unit and the meter 8 istransmitted to other nodes, the above-mentioned group or the electricpower supplier 1, and the electric power selling/purchasing system 7finds out a node outputting an information signal meaning that electricpower can be sold in accordance with the above-mentioned transmittedinformation near the node, from which electric power is purchased andtransmits electric power selling request information (the request amountof electric power supply) to the node. For example, informationregarding the identification number of the node requesting the sellingof electric power and the amount of electric power requested to be soldis transmitted to the electric power transmission lines by using smallpulses.

Furthermore, the electric power selling/purchasing system 7 monitors thepulses transmitted to the electric power transmission lines; when theelectric power selling/purchasing system detects the identificationnumber of the node to which the system itself belongs, it transmits theinformation subsequent thereto. If the information is electric powerselling request information, electric power is transmitted to theelectric power transmission lines in accordance with the information.

In the above-mentioned embodiment, the information transmitted by theelectric power selling/purchasing system 7 is the electric power storageamount of the storage battery; however, without being limited to theelectric power storage amount, the extra capacity of the electric powergenerator (the value obtained by subtracting the amount of electricpower consumption predicted at present or in the future from the maximumoutput or the most efficient output of the electric power generator) maybe transmitted. Both may also be transmitted as a matter of course.

Moreover, the available capacity of the storage battery (the amount ofelectric power that can be stored further in the storage battery, inother words, (the capacity of the storage battery)−(the electric powerstorage amount of the storage battery)), may be transmitted so that theselling of electric power from a node, in which its storage batterybecomes full and its electric power is highly unlikely to be usedeffectively, has higher priority.

Still further, the capacity of the storage battery may be memorized inadvance in an apparatus for determining the amount of electric power,which is sold by each anode, and both the value of the electric powerstorage amount and the available capacity of the storage battery may beused as information regarding the electric power storage amount of thestorage battery to determine the amount of electric power to be soldfrom each node. If the available capacity of the storage battery isknown, the amount of electric power unable to be stored in the storagebattery and thus wasted can be reduced.

Still further, each node 2 is not always required to have the storagebattery 5. When the node does not have the storage battery 5, electricpower selling request information may be formed by using informationregarding the electric power generator 4, such as the extra capacity ofthe electric power generator 4.

Still further, a node without the electric power generator 4 may also beused. In this case, the node should only be dealt with such that itssalable amount of electric power is zero. In addition, in theabove-mentioned embodiment, the salable amount of electric power and thepurchasable amount of electric power (in other words, transfer amountinformation regarding the transfer amount of energy) to be transmittedfrom the meter 8 and the information regarding the salable amount ofelectric power (in other words, information regarding the electric powerstorage amount of the storage battery) to be transmitted from theelectric power selling/purchasing system 7 are transmitted separately;however, both may be transmitted together by means of the electric powerselling/purchasing system 7 and information can be transmittedefficiently by such a transmission.

Still further, in the above-mentioned embodiment, a signal indicatingthe amount of electric power that can be supplied is transmitted asinformation regarding the electric power supply capacity; however, onlythe information as to whether electric power can be supplied or not maybe transmitted as information regarding electric power supply capacityfrom the anode 2, and only the information as to whether electric poweris permitted to be sold or not may be received at the anode 2 asinformation for increasing/decreasing the electric power supplycapacity.

Still further, in the above-mentioned embodiment, information istransmitted via the electric power transmission system by using theelectric power transmission lines; however, without being limitedthereto, the telephone lines, wireless transmission or the lines of ACelectric power sources may also be used, for example. When using theelectric power transmission lines, the lines are advantageous since itis not necessary to prepare new transmission lines and the like. On theother hand, when not using the electric power transmission lines, thismethod is advantageous since information transmission is possible evenwhen the electric power transmission lines are affected by trouble, suchas a thunderbolt.

EMBODIMENT 2

FIG. 2 is a view showing the configuration of an electric power supplyand demand management system in accordance with Embodiment 2 of thepresent invention. In FIG. 2, electric power transmission lines 40 arehigh-voltage electric power transmission lines and have a high voltagein order to efficiently transmit electricity from an electric powersupplier, such as a thermal electric power station, to nodes 2, such asresidential areas. Electric power transmission lines 50 and electricpower transmission lines 150 are transmission lines for transmitting avoltage to be supplied to each node; for example, the voltage iscontrolled so as to be maintained at a constant voltage in the range ofabout 100 to 220 V.

A substation 10 belonging to the electric power supplier is providedbetween the electric power transmission lines 40 and the electric powertransmission lines 50 and transforms the voltage across the electricpower transmission lines 40 to the voltage across the electric powertransmission lines 50. The relation between the electric powertransmission lines 40 and the electric power transmission lines 150 issimilar to that described above. To the substation 10, 99 numbers ofnodes 2 are connected, whereby electric power can be sold or purchased.The amount of electric power transformed by the substation can bemeasured by an ammeter 20, and the result of the measurement (in otherwords, electric power demand information regarding the movementdirection and the amount of electric energy flowing through the electricpower transmission lines) is sent to a salable electric power pricesetting apparatus 30. This ammeter 20 and the price setting apparatus 30constitute the first calculation unit or the second calculation unit.

When energy flows from the electric power transmission lines 50 to theelectric power transmission lines 40, the price setting apparatus 30lowers the selling price of electric power having been set at present(in other words, information for increasing/decreasing the amount ofelectric power to be sold by each node), and notifies the price to the99 numbers of nodes 2. In the case when the electric power generationcost at the node 2 itself is higher than the selling cost of theelectric power, the output of its electric power generator is lowered orthe electric power generator is stopped, whereby the sale of electricpower can be stopped. This can prevent the sale of electric power from aregion to which electricity is supplied from the substation 10.

On the other hand, when energy flows from the electric powertransmission lines 40 to the electric power transmission lines 50, theprice setting apparatus 30 raises the selling price of electric powerhaving been set at present, and notifies the selling price to the 99numbers of nodes 2. However, when the price-is close to the price ofelectricity that can be supplied by another means, such as a means forobtaining electricity from a thermal electric power station or the likethrough the electric power transmission lines 40, the selling price ofelectric power is not raised.

In the case when the electric power generation cost at each of the 99numbers of nodes 2 is lower than the selling price of the electricpower, the output of its own electric power generator is raised or theelectric power generator is activated, whereby the sale of electricpower can be started. This can promote the sale of electric power fromthe region to which electricity is supplied from the substation 10.

As described above, the amount of energy (electric power) passingthrough the substation 10 decreases, whereby the electric powertransmission loss between substations or between a substation and anelectric power station can be reduced. Furthermore, this relation issimilar to the relation among a substation 110, an ammeter 120, a pricesetting apparatus 130, the electric power transmission lines 40, theelectric power transmission lines 150 and nodes 101 in another group. Inother words, by dividing a plurality of nodes into a plurality of groupsand by balancing the supply and demand of electric power in each group,it is possible to reduce the electric power transmission loss of thewhole system.

In the case when the difference between the price set by the pricesetting apparatus 30 and the price set by the price setting apparatus130 is larger than the total electric power transmission loss of thesubstation 10, the electric power transmission lines 40 and thesubstation 110, the price at each node may be set referring to thepreset price at another node. For example, in the case when the priceset by the price setting apparatus 130 becomes larger than the sum ofthe price set by the price setting apparatus 30 added to the totalelectric power transmission cost of the substation 10, the electricpower transmission lines 40 and the substation 110, the selling price ofelectric power is set as described below.

-   -   (1) When electric power flows from the electric power        transmission lines 40 to the electric power transmission lines        50, the price setting apparatus 30 raises the selling price of        electric power.    -   (2) When electric power flows from the electric power        transmission lines 150 to the electric power transmission lines        40, the price setting apparatus 130 lowers the selling price of        electric power.    -   (3) In the cases other than the cases (1) and (2), and in the        case when the total of the amount of electric power flowing from        the electric power transmission lines 40 to the electric power        transmission lines 150 (this becomes a minus value when electric        power flows from the electric power transmission lines 150 to        the electric power transmission lines 40) and the amount of        electric power flowing from the electric power transmission        lines 40 to the electric power transmission lines 50 is larger        than zero, the price setting apparatus 30 raises the selling        price of electric power.    -   (4) In the cases other than the cases (1) and (2), and in the        case when the total of the amount of electric power flowing from        the electric power transmission lines 150 to the electric power        transmission lines 40 (this becomes a minus value when the        electric power flows from the electric power transmission lines        40 to the electric power transmission lines 150) and the amount        of electric power flowing from the electric power transmission        lines 50 to the electric power transmission lines 40 is larger        than zero, the price setting apparatus 30 lowers the selling        price of electric power.

In the above-mentioned embodiment, the supply and the demand of electricpower are balanced by changing the selling price of electric power usedas information for increasing/decreasing the amount of electric powersupply; however, the supply and the demand may be balanced by changingthe purchase price of electric power used as information forincreasing/decreasing the amount of electric power supply or by changingboth the selling price and the purchase price of electric power used asinformation for increasing/decreasing the amount of electric powersupply.

EMBODIMENT 3

FIG. 3 is a view showing the configuration of an electric power supplyand demand management system in accordance with Example 3 of the presentinvention. Example 3 shown in FIG. 3 is the same as Example 1 in thateach node has electric power consuming apparatuses, an electric powergenerator and a storage battery, but different in that the electricpower selling/purchasing system 7 used as a second calculation unitdetermines the selling price of electric power.

The electric power selling/purchasing system 7 sets the selling price ofelectric power on the basis of information, such as the current electricpower supply capacity and the electric power storage amount stored inthe storage battery. For example, the selling price of electric powermay be set by subtracting a constant value from a limit cost per unit ofelectric power of the present electric power generator, or the sellingprice of electric power may be set lower on the basis of the electricpower storage amount of the storage battery when the electric powerstorage amount is large.

The electric power selling/purchasing system 7 converts information foridentifying the node to which the system itself belongs and informationregarding the selling price of electric power and the salable amount ofelectric power into pulse signals and transmits the signals as electricpower selling bid information to the electric power transmission system3. The electric power selling bid information is collected at onelocation or at each region and received by nodes or electric powersuppliers demanding electric power; these nodes and electric powersuppliers competitively transmit electric power selling requestinformation (successful bid information) to the node that transmittedthe above-mentioned electric power selling bid information.

In other words, in the electric power supply and demand managementsystem of the present invention, a node requiring electric powercompares the selling prices of electric power presented by electricpower suppliers and other nodes capable of selling electricity fromtheir electric power generators, thereby being able to acquire electricpower at a lower price.

An example of a method of retrieving bid information stating that a noderequiring electric power purchases (is supplied with) electric power ata low price will be described. For example, a table comprising bidinformation including the identification number of each node, sellingprice of electric power and salable amount of electric power is preparedas shown in FIG. 4. The node requiring electric power is then subjectedto the following processing.

First, values are obtained by dividing the selling price of electricpower at each node capable of selling electric power by its electricpower transmission efficiency, and a node X having the minimum value isfound out. The electric power transmission efficiency can be obtained by(the amount B of electric power receivable by a node that receiveselectric power)/(the amount A of electric power transmitted by a nodethat sells electric power). Furthermore, the increase of the amount ofelectric power, which is converted into heat owing to change in current,the resistance of transmission lines and the like during electric powertransmission from an electric power selling node to a node requiringelectric power, becomes A-B.

In the case when the amount of electric power that can be supplied(sold) by the node X is larger than the value obtained by dividing theamount of electric power, which is required by a node demanding electricpower, by the electric power transmission efficiency, a value obtainedby dividing the required amount of electric power by the electric powertransmission efficiency is added to the selling amount of electric power(bid information) requested to the node X.

On the other hand, in the case when the amount of electric power thatcan be supplied (sold) by the node X is smaller than the value obtainedby dividing the amount of electric power, which is required by a nodedemanding electric power, by the electric power transmission efficiency,the amount of electric power that can be supplied is added to theselling amount of electric power (bid information) requested to theabove-mentioned node X.

The required amount of electric power can be obtained by ((the amount ofelectric power required by a node demanding electric power)−(the sellingamount of electric power requested to a node selling electricpower))×(electric power transmission efficiency).

Next, a similar calculation is carried out for nodes wherein valuesobtained by dividing the selling prices of electric power by theelectric power transmission efficiency are small, and this calculationis repeated until the required amount of electric power becomes zero.After the above calculation is completed for all nodes demandingelectric power, the selling amounts of electric power (bid information)are transmitted to all the nodes requesting the sale of electric powervia the electric power transmission system. Hence, electric power issold to nearby nodes demanding electric power, whereby the sale andpurchase of electric power can be done efficiently.

EXAMPLE 4

FIG. 5 is a view showing the configuration of an electric power supplyand demand management system in accordance with Embodiment 4 of thepresent invention. Embodiment 4 shown in FIG. 5 is the same asEmbodiment 1 in that each node has electric power consuming apparatuses,an electric power generator and a storage battery, but different in thatthe operation of the electric power selling/purchasing system isdetermined depending on voltage by using the fact that the voltagechanges depending on electric power supply and demand situation. Inother words, the voltage lowers when electricity is supplied to a nearbynode via the transmission lines, and the voltage rises when electricityis supplied reversely; hence, electric power may be sold when thevoltage is low, and electric power may be prevented from being sold whenthe voltage is high.

More specifically, the electric power selling/purchasing system 7determines as to whether electric power is sold or not depending on theelectric power storage amount at the storage battery 5 and the voltagesignal from a voltmeter 9, and also determines the amount of electricpower to be sold, and then sell the electric power. As a result,electric power can be sold when electric power is demanded near thenode, whereby electric power can be used efficiently as a whole in theelectric power supply and demand management system.

In addition, when distributed processing is carried out at each node asin the example, even if an accident occurs, for example if a part of theelectric power transmission lines of the electric power transmissionsystem is cut off, the electric power supply and demand managementsystem is controlled so that supply and demand are balancedautomatically at portions connected by the electric power transmissionlines, thereby being advantageous.

In the case when the voltmeter 9 does not operate accurately, there isdanger that nodes selling electric power might be concentrated onlimited nodes. For example, in the case when it is set that electricpower is sold when the voltages of the electric power transmission linesconnected to two adjacent nodes are almost the same and when thevoltages at the two nodes are constant (for example 100 V) or more, theselling of electric power from the node, the measured voltage of whichis slightly lower, has higher priority.

To solve the above-mentioned problem, electric power should be sold byfurther considering the amount of electric power stored in the storagebattery or the voltage should be measured accurately. FIG. 6 is a viewshowing the configuration of an example of a circuit for measuring thevoltage accurately. In FIG. 6, reference voltage (the desirable voltageof the electric power transmission lines) lines 3 b as well as electricpower transmission lines 3 a in the electric power transmission systemare connected to the voltmeter 9 of each node. A switch S1 and a switchS2 are switches for connecting the electric power transmission lines 3 aor the reference voltage lines 3 b to a rectifier 9 a. Alternatingcurrent from the electric power transmission lines 3 a or the referencevoltage lines 3 b is rectified to direct current by the rectifier 9 aand converted into a digital signal representing a voltage by ananalog/digital converter 9 b. A control circuit 9 c transmits a voltagesignal obtained by dividing the voltage value across the electric powertransmission lines 3 a by the reference voltage value to the electricpower selling/purchasing system 7. Since the electric power transmissionlines 3 a and the reference voltage lines 3 b are measured by using thesame rectifier 9 a and the analog/digital converter 9bid is possible toobtain signals wherein errors due to variations in parts and the likeare cancelled.

EMBODIMENT 5

FIG. 7 is a view showing the configuration of an electric power supplyand demand management system in accordance with Embodiment 5 of thepresent invention. In the electric power supply and demand managementsystem of this embodiment, twp nodes 101 and 201 are included in onegroup. In FIG. 7, a fuel cell 104 and a fuel cell 204 used as electricpower generators are shown separately from the node 101 and the node201, respectively, for the sake of convenience; however, they areincluded in the node 101 and the node 201, respectively, actually.

Furthermore, when the amounts of electric power consumption at the nodesare measured by electric power distribution boards 102 and 202,respectively, as shown in FIG. 7, an electric power consuming apparatus,which receives electric power supplied from the correspondingdistribution board, or a set of such electric power consumingapparatuses becomes a node; this is advantageous in that the amounts ofelectric power consumption of the electric power consuming apparatuses,which are physically adjacent to each other, that is, have the sameelectric power transmission loss on the basis of a certain fuel cell,can be measured together. For example, nodes having higher electricpower transmission efficiency by electric power transmission from thefuel cell 204 rather than by electric power transmission from the fuelcell 104 can be measured together by a wattmeter 203. The amounts ofelectric power consumption of the node 101 and the node 201 are measuredby a wattmeter 103 and the wattmeter 203, which are measurement means,respectively.

The wattmeter may perform measurement by counting the number ofrevolutions of a disc, which rotates depending on the amount of electricpower consumption, or by calculating the sum of current values, whichare obtained by measuring current or the like, with the use of an ADconverter at constant time intervals. Data measured by the wattmeter 103and the wattmeter 203 is transmitted to a storage means 301, which is astorage unit, and stored therein.

The storage means 301 memorizes the amount of electric power consumptionin every time zone as a table as shown in FIG. 8, for example. Since thecapacity of the storage means 301 is limited, when the free space of thestorage area thereof is lost or becomes small, new data (current data)is stored while older data is deleted. The data recorded in the storagemeans 301 is read by predicting means 302 and used as a parameter forpredicting the amount of electric power consumption. The firstcalculation unit or the second calculation unit may be used to functionas the predicting means 302 and supplied amount determining means 303.

The amount of electric power consumption is predicted as describedbelow. For example, when the node is a general household and no data isavailable in the storage means 301 (for example, immediately after thecontrol apparatus is installed), a standard electric power chargeobtained depending on the number of family members, family structure,season, etc. is used as it is. When data for one or more days is storedin the storage means 301, the amount of electric power consumption canbe predicted by averaging data in the same time zone. Furthermore, thehour of rising and the number of family members at home are differentdepending on weekday or holiday; therefore, the amount of electric powerconsumption can be predicted accurately by averaging past electric powercharges depending on weekday, holiday or a day of week.

In addition, the amounts of electric power consumption of an airconditioner and the like differ depending on the season; hence, theamounts of electric power consumption can be predicted highly accuratelyby averaging the amounts of electric power consumption every season, bydeleting the data of the amounts of electric power consumption in acertain period of the past or by not using the data of the amounts ofelectric power consumption in a certain period of the past when takingan average. Furthermore, the amounts of electric power consumptiondiffer depending on weather; hence, the amounts of electric powerconsumption can be predicted highly accurately by averaging the amountsof electric power consumption depending on the weather conditions.Moreover, the amounts of electric power usage differ depending on theschedule information of each day (for example, nobody at home because oftravel, no school because of summer vacation, returning home late,visitors at home, etc.); hence, the amounts of electric powerconsumption can also be predicted highly accurately by dividing theschedule information into a plurality of categories and by taking anaverage for each category.

The categories are assumed to be weekday and holiday; spring, summer,fall and winter; school day or no school day; weather; visitors at homeor not; plan to go out; plan to take a bath; and other situationsaffecting the amounts of electric power consumption and the combinationsof them. The schedule information may be input from a personal computeror the like, which is used as a control unit for managing a schedule ateach node and connected to the electric power supply and demandmanagement system, or may be received from the electric power supplier.

Furthermore, information estimated from the amount of electric powerconsumption in the morning or the like may be used as the scheduleinformation. In other words, for example, since the hour of rising islate during a holiday, if the amount of electric power consumption,which would begin to increase at a certain time of the day in the caseof a weekday, remains small, it may be judged that today is a holiday;or it may be judged that nobody is at home if the home security systemis in its absent mode.

Moreover, the amounts of electric power consumption of the past may becategorized as described above and they may be reflected to the scheduleinformation; furthermore, the amount of electric power consumptionpredicted as described above may be changed by using the scheduleinformation. For example, in the case when a resident was not at homeuntil 18:00 and he returned at 18:00, an air conditioner or the like isturned on, whereby the amount of electric power consumption increasesusually; hence, the final amount of electric power consumption may beobtained by averaging the amounts of electric power consumption of thepast in the case when he is at home all day and by adding the amount ofelectric power consumption predicted to increase (the amount ofincrease) to the average.

The amount of increase to be added differs depending on season; hence,it may be based on data prepared for each category, may be obtained froma predetermined calculation formula by using a parameter affecting theamount of electric power consumption, such as temperature and weather,or may be obtained by averaging actual measurement values.

The above-mentioned actual measurement values are obtained as describedbelow, for example. Namely, the average of the actual measurement valuesof the amounts of electric power consumption in the case when theresident is at home all day and the actual measurement value of theamount of electric power consumption during a certain time having passedafter the resident returned home in the middle of the day are obtained,and the difference between the above average value and the actualmeasurement value is memorized. The average of the differences obtainedin the same manner in the same category is used as the amount ofincrease to be added. As described above, the supplied amountdetermining means 303 determines the supplied amount of electric poweron the basis of the amount of electric power consumption predicted bythe predicting means 302.

Since two fuel cells are used in the electric power supply and demandmanagement system shown in FIG. 7, the supplied amount of electric powerfrom each fuel cell differs depending the characteristic of the fuelcell and an electric power transmission loss between the fuel cell tothe node. In the case when the node 101 is distant from the node 201 andwhen an approximate efficiency is determined by the electric powertransmission loss between the node 101 and the node 201, the predictedamounts of electric power consumption at the node 101 and the node 201may be used directly as the supplied amounts of electric power of thefuel cell 104 and the fuel cell 204 as a general rule. Furthermore, inthe case when the amount of electric power consumption predicted at eachnode exceeds the electric power supply capacity of its fuel cell,electric power may be supplied from the fuel cell of the other node.

For example, in the case when the output of the fuel cell at one of thenodes is small, the characteristic of the fuel cell is efficient and theelectric power transmission loss between the node 101 and the node 201is small, both the fuel cells may always be activated, whereby theelectric power may be distributed to the two nodes equally. In otherwords, a plurality of fuel cells are activated and managed in a groupand necessary electric power is supplied to the nodes in the group. Inthis case, the amount of electric power consumption measured by thewattmeter 103 may be added to that measured by the wattmeter 203, andthe total may be stored in the storage means 301.

On the other hand, in the case when the output of the fuel cell at oneof the nodes is large, the characteristic of the fuel cell is efficient,the electric power transmission loss between the node 101 and the node201 is small and necessary electric power can be supplied only byactivating one of the fuel cells, only the fuel cell belonging to thenode, wherein the predicted amount of electric power consumption islarger, may be activated to supply electric power.

Alternatively, data representing the relation between the output of anelectric power generator and the usage amount of fuel (for example, datashown in FIG. 10) may be memorized, and the most suitable amount ofelectric power generation of each fuel cell may be obtained bycalculation or simulation from the memorized content. Furthermore, sincethe amount of change per hour in the amount of electric power supply ofthe fuel cell has a limit, the amount of electric power supply may bedetermined so that the amount of the change is a predetermined value orless.

Next, a supply control means 304 operated valves 105 and 205 for fuel,such as gas depending on the supplied amount determined by the suppliedamount determining means 303. Since the output of the fuel cell does notincrease immediately after the valve for fuel, such as gas, is opened,the amount of operation of the fuel valve is determined on the basis ofthe amount of electric power supply for the next two hours. Furthermore,in the above-mentioned embodiment, the amount of electric powerconsumption once measured is memorized, the memorized content is readand the amount of electric power consumption is predicted; however, themethod described below may also be used.

Namely, the standard amount of electric power consumption for a day ismemorized in the storage means 301 first. When the measurement result ofthe amount of usage is received, z=ay+x(1−a) is obtained by using theamount x of electric power consumption at that time and the amount y ofelectric power consumption measured at the present time from thecontents memorized in the storage means 301, and z at that time ismemorized instead of x in the storage means 301 (a is a predeterminedcoefficient satisfying the relation 0<a<1).

The amount of electric power consumption can be predicted by using thecontents stored in the storage means 301. In this manner, averaging canbe carried out while highly weighting measurement data, which areobtained at times close to one another, thereby being advantageous inthat only a small amount of storage capacity is required. Furthermore,in the above-mentioned embodiment, the amount of electric powerconsumption was measured and the amount of electric power consumptionwas predicted by using the measurement value; however, it is not alwaysnecessary to measure the amount of electric power consumption, but thestandard amount of electric power consumption may be directly used asthe predicted value of the amount of electric power consumption.

Still further, in the above-mentioned embodiment, a case wherein fuelcells are controlled was explained; however, the electric powergenerators are not limited to the fuel cells, but other types ofelectric power generators, such as gas turbines, may be controlled. Thepresent invention is particularly effective when controlling an electricpower generator that cannot change its amount of electric power supplyin a short time.

EMBODIMENT 6

The above Embodiment 5 in accordance with the present invention can beattained with the use of circuits; however, the present invention canalso be attained with the use of a CPU, memory and peripheral circuits.In this case, the flowchart of a program for determining the operationof the CPU is shown in FIG. 9. Step 1 is to realize the storage means301, step 2 is to realize the predicting means 302, step 3 is to realizethe supplied amount determining means 303, and step 4 is to realize thesupply control means 304. These steps are not always required to becarried out in the above order. Furthermore, operation is carried out atintervals of 10 minutes in FIG. 9; however, the operation may be carriedout at intervals other than 10 minutes, and the operation may be carriedout at intervals different from one another.

For example, step 1 to step 4 may be carried out as four processesindependent from one another. In other words, process 1 and process 4may be carried out at intervals of 10minutes, and process 2 and process3 may be carried out in time zones (for example at night) during whichthe CPU is idle.

Furthermore, programs (any programs, such as source programs, objectprograms, etc., regardless of the type of execution) for activating theCPU are stored on a recording medium that can be read by a computer, andthen transferred (sold), or only the contents of the programs aredistributed via communication lines, and the contents are finally storedin memory constituting an electric power supply control apparatus,whereby the electric power supply control apparatus can be realized.

INDUSTRIAL APPLICABILITY

The present invention can provide an electric power supply and demandmanagement system and energy management system capable of efficientlycontrolling and managing the supply and demand of electric power whilereducing electric power transmission loss by selecting a node that cansell electric power from the electric power generator thereof to anelectric power supplier depending on the demand of the node.

Furthermore, the present invention can provide an electric power supplyand demand management system that can allow a fuel cell used as anelectric power generator to generate an appropriate amount of electricpower, not excessive or lacking.

1. An electric power supply and demand management system comprising: an electric power supplier; an electric power transmission system; electric power consuming nodes, each having an electric power generator, connected to said electric power transmission system and classified into groups, each comprising a plurality of nodes; a first calculation unit configured to obtain a difference between a total of electric power supplied from said electric power supplier to said node or said group and a total of electric power consumed by an electric power load of said node or said group; and a first transmission unit configured to transmit information for increasing/decreasing an amount of electric power supply to said electric power supplier so that said difference becomes smaller, wherein said first calculation unit determines at least one of a selling price of electric power from said electric power supplier to said node or said group and a purchase price of electric power purchased from said node or said group and sold to said electric power supplier, by using said difference between a total of electric power supply from said electric power supplier to said node or said group and a total of electric power consumed by an electric power load at said node or said group as a parameter, and said first transmission unit transmits at least one of said selling price and said purchase price to said node or said group, wherein said electric power supplier has a reception unit configured to receive information selected from the group consisting of an electric power charge, an amount of electric power consumption and an electric power supply capacity of said node or said group, said first calculation unit determines an amount of electric power and a purchase price of electric power demanded by said electric power supplier for each node, which can sell electric power among said nodes, on the basis of said information selected from the group consisting of an electric power charge, an amount of electric power consumption and an electric power supply capacity of said node or said group, and said first transmission unit transmits at least one of said amount of electric power and said purchase price demanded by said electric power supplier to said node.
 2. The electric power supply and demand management system in accordance with claim 1, wherein said node or said group is provided with; a second transmission unit configured to transmit information selected from the group consisting of an electric power charge, an amount of electric power consumption and an electric power supply capacity to other nodes, groups or said electric power supplier; a second reception unit configured to receive information selected from the group consisting of an amount of electric power, a purchase price of electric power and a selling price of electric power demanded by said other nodes, groups or said electric power supplier; and a control unit configured to control an output of said electric power generator of said node on the basis of said information.
 3. The electric power supply and demand management system in accordance with claim 2, comprising, a node information storage unit configured to store node information including a node identifier for identifying said node and an amount of electric power consumption and an amount of electric power supply of said node identified by said identifier, wherein said first calculation unit calculates an amount of transmittable electric power from one node to other nodes and/or said electric power supplier by using said amount of electric power consumption and said amount of electric power supply included in said node information as parameters, said first transmission unit transmits a signal indicating said amount of transmittable electric power to each node, and said node transmits said transmittable electric power to the other nodes and/or said electric power supplier.
 4. The electric power supply and demand management system in accordance with claim 1, wherein said electric power supplier has a substation, said first calculation unit calculates a purchase amount of electric power and a purchase price of electric power, which are demanded by said electric power supplier, by using electric power supply and demand information regarding a flowing direction and an amount of energy between a high-voltage side to a low-voltage side of said substation, and said first transmission unit transmits said amount of electric power to be purchased and said purchase price to said node or said group.
 5. The electric power supply and demand management system in accordance with claim 1, wherein said node is provided with a storage battery, and a second calculation unit configured to determine at least one selected from the group consisting of a purchase amount of electric power, a purchase price of electric power, a selling amount of electric power and a selling price of electric power, which are demanded for said other nodes, by using information regarding electric power demand and storage amounts of storage batteries connected to other nodes, and said second transmission unit transmits at least one selected from the group consisting of a purchase amount of electric power, a purchase price of electric power, a selling amount of electric power and a selling price of electric power to at least one of said electric power supplier and the other nodes.
 6. The electric power supply and demand management system in accordance with claim 1, wherein said first calculation unit or said second calculation unit predicts an amount of electric power consumption of said node or said group and determines an amount of electric power supply, which is demanded by said node or said group, by using said predicted amount of electric power consumption as a parameter, and said first transmission unit or said second transmission unit transmits a signal in order for an electric power generator of a node or a group other than said node or said group, or for said electric power supplier to supply said amount of electric power.
 7. The electric power supply and demand management system in accordance with claim 1, comprising an electric power consumption amount storage means configured to store information regarding an amount of electric power consumption of each node, and said first calculation unit or said second calculation unit predicts an amount of electric power consumption of each node or each group by using said stored amount of electric power consumption as a parameter.
 8. The electric power supply and demand management system in accordance with claim 6, wherein said first calculation unit or said second calculation unit determines an amount of electric power supply from said node by using data including a relation between an output of said electric power generator and an amount of fuel consumption as parameters.
 9. The electric power supply and demand management system in accordance with claim 6, wherein said first calculation unit or said second calculation unit determines an amount of electric power supply from said electric power generator by using at least said amount of electric power consumption of said node as a parameter.
 10. The electric power supply and demand management system in accordance with claim 9, wherein said first calculation unit or said second calculation unit determines an amount of electric power supply of each electric power generator so that the number of electric power generators in operation of said nodes becomes minimum or maximum.
 11. The electric power supply and demand management system in accordance with claim 9, wherein said first calculation unit or said second calculation unit predicts an amount of electric power consumption of each node by using a schedule information.
 12. The electric power supply and demand management system in accordance with claim 9, wherein said first transmission unit or said second transmission unit transmits information for increasing/decreasing an amount of electric power supply from a storage battery of said each node or said electric power generator connected to said storage battery to a node, which requires electric power, by using information regarding a storage amount of said storage battery or information regarding a transfer amount of energy of each node.
 13. The electric power supply and demand management system in accordance with claim 1, wherein said electric power supplier has a reception unit for receiving information selected from the group consisting of an electric power charge, an amount of electric power consumption and an electric power supply capacity of said node or said group, said first calculation unit determines an amount of electric power and a purchase price of electric power demanded by said electric power supplier for each node, which can sell electric power among said nodes, on the basis of said information, and said first transmission unit transmits at least one of said amount of electric power and said purchase price demanded by said electric power supplier to said node.
 14. The electric power supply and demand management system in accordance with claim 1, wherein said node or said group is provided with; a second transmission unit configured to transmit information selected from the group consisting of an electric power charge, an amount of electric power consumption and an electric power supply capacity to other nodes, groups or said electric power supplier; a second reception unit configured to receive information selected from the group consisting of an amount of electric power, a purchase price of electric power and a selling price of electric power demanded by said other nodes, groups or said electric power supplier; and a control unit configured to control an output of said electric power generator of said node on the basis of said information. 